缺血性脑卒中大鼠褪黑素及其受体改变及褪黑素预处理的保护作用

CHANGES OF MELATONIN AND ITS RECEPTOR IN ISCHEMIC CEREBRAL APOPLEXY RATS AND EFFECT OF PRETREATMENT WITH MELATONIN.

借助缺血性脑卒中SD大鼠模型 ,测定血清皮质酮及褪黑素 (Mel)浓度 ,[12 5I] Mel特异结合测定大鼠脑组织及外周血白细胞褪黑素受体(MR)的放射活性 ,计算其最大结合容量和平衡解离常数。研究缺血性脑卒中大鼠Mel及其受体改变及Mel预处理的影响。结果显示 ,脑卒中组血清皮质酮浓度明显高于假手术组 (P <0 0 1) ,与应激程度相符 ,Mel组其升高幅度减低。脑卒中组及假手术组Mel水平升高 (均P <0 0 1) ,与应激程度相符。脑卒中组和假手术组MR结合容量均降低 ,脑卒中组降低更明显 ,Mel组MR结合容量较脑卒中组为高。MR在脑组织中和白细胞的改变明显相关。研究提示 ,缺血性脑卒中SD大鼠血清Mel水平升高与应激反应有关 ,白细胞MR可代表脑组织MR的变化 。

The aim of this study was to observe the changes of melatonin and its receptor in ischemic cerebral apoplexy(ICA) rats and the effect of melatonin pretreatment on The ICA rats. The ICA rat model was reproduced by using Pulsinelli′s method. Serum corticosterone and melatonin concentration were determined in each group. The radioactivity of melatonin receptor in the brain and peripheral leucocytes was deteced by -Mel radioligand binding assay. Bmax and Kd of melatonin receptor were calculated. The results indieated serum corticosterone in apoplexy group was higher than in sham operation group (P<0.01). The rise of serum corticosterone was consistent with the degree of stress. Serum corticosterone in Mel group was lower than that in apoplexy group. Melatonin concentration in apoplexy group and sham operation group rose significantly (both P<0.01), matching with the degree of stress. Bmax of melatonin receptor reduced in apoplexy and sham operation groups and was lower in apoplexy group than in sham operation group. Bmax of melatonin receptor in Mel group was higher than that in apoplexy group. The changes of melatonin receptor in brain was significantly related with change in leucocytes. Our study indicates the rise of serum melatonon concentration in ICA rats is related to stress. Melatonin receptor in leucocytes can represent its change in the brain. Melatonin can protect the brain of ICA rats.